Re: HD 189735

[Tom Droege <tdroege2@earthlink.net>]

I should have more data on this one.  If someone will remind me of the 
decimal RA and Dec. I will look.

Tom Droege

At 10:29 AM 9/10/02 +0000, you wrote:

>Michael and each
>
>I'd been looking at this one.
>
>The TASS data says it's an RS CVn variable caught at one secondary
>minimum and also with the maximal wave sampled too over several
>different nights.  The eclipse gets bluer, so it is secondary.  Primary
>eclipse may end up being as much as a mag.
>
>You are a long way off folding the current data into anything.  RS CVn
>light curves need serious and complete sampling, and can vary over time
>for various reasons (though more usually over the longer term) so
>folding isn't entirely safe.
>
>
>Probably ought to check with Dirk re nature (B-V may be a bit too
>"early" for RS CVn identification) and import: I believe RS CVn objects
>are not that common.  Period is gonna be a day or more, with a lot more
>also being possible.  Could be a significant find and worthy of a
>multi-observer campaign.  A good light curve gives rotation rate of
>secondary star as well as orbital period, though the vast majority of
>these stars are synchronous (or "pseudosynchronous" if the orbit is
>elliptical), so there should be could be no difference twixt the two.
>Showing whether object is asynchronous or not is an important part of
>collecting the light curve.  Collecting lightcurves at times over many
>years allows solar-type cycle to be assessed.  A good lifetime project
>one.
>
>Strangely no hint of xray source.  As you say, not previously known.
>
>Cheers
>
>John